How to tell when a Generic Camera Image is Stale?

I’m using a still-image url in the Generic Camera Integration that updates every 10 seconds.

Many of these cameras are very remote and the connection often goes down for brief periods.

I would like to be able to determine programmatically when the image is Stale (over 60 seconds old).

So I would like to be able to detect this and update, possibly the state_filter on the picture-entity, to reflect that the image is old/stale if its not been refreshed in over a minute.

This is related to my post in Configuration->Frontend:

Any ideas?

Thanks!

Run a command line on the filename to extract the date/time, e.g. fro ubuntu

stat -c '%y' [filename] 

could kick back: 2023-03-23 11:16:15.279167100 +0100
which you can then rework, either already in the cmd line sensor (value template) or afterwards
I donot have the end2end solution so just ideas